Dental chair.



F. E. CASE.

DENTAL CHAIR.

APPLICATION man AUG. 16, 1912.

1, 173,557. Patented Feb. 29, 1916.

6 SHEETSSHEET laww/wlio o n W Gm w W .W

F. E. CASE.

DENTAL CHAIR.

APPLICATION FILED AUG. 16. 1912.

Patented; 1 613. 29,1916.

6 SHEETS-SHEET 2- F. E. CASE.

DENTAL CHAIR.

APPLICATION FILED nus. I6. 1912.

Patented Feb. 29, 1916.

6 SHEETSSHEET 3.

n77 5 V b 0 Q I w v I I -/6 .MQV. v I

F. E. CASE.

DENTAL CHAIR. APPLICATION FILED AUG. 16, I912.

Patented Feb. 29, 1916.

6 SHEETS SHEET 4- n 2 z o w w w F. 'E. CASE.

DENTAL CHAIR.

APPL ICATION FILED, AUG. 16, 1912. I

Patented Feb. 29,1916.

6 SHEETSSHEET 5- m) 2 mm F. E. CASE.

DENTAL CHAIR.

APPLICATION EILED AUG. l6| I912.

Patented Feb. 29

w w 9 W 2 NW 8 F 7 M 5 w'i bmeooeo (74% Canton, in the county of Stark and FRANK E. case, or can'rou, 01110,

assienon To THE HARVARD comramz, or can'ron,

OHIO, A CORPORATION OF OHIO.

pnnrar. seam.

. Specification of Letters Patent.

PatentedFeb.29,1916.

Application filed August 16, 1912. serial No. 715.323.

T 0 all whom it may concern:

Be it known that I, FRANK E. CASE, a citizen of the United 1 States, residing at State of Ohio, have invented certain new and useful Improvements in Dental Chairs, of which the following is a specification.

The invention relates to chairs of the kind generally used by dentists, surgeons, barbers and others wherein the seat frame of the chair is mounted on a rotatable and vertically extensible pedestal; and the general objects of'the invention are to construct the chair parts and the jack parts in such manner that the jack, as a whole, or the working parts thereof, can be readily entered and removed through the upper end of the pedestal, and provide means for automatically coiirdinating the operating of the release valve with the extreme movements of the extensible pedestal.

The objects of the invention, thus set forth in general terms, are attained by the preferred embodiment thereof illustrated in the accompanying drawings, forming part hereof, in wh1ch- Figure 1 is aperspective view of the chair with the seat cushion removed and showing the jack removed from the pedestal; Fig. 2,

a vertical section showing the pedestal standards extended and showing a side elevation of the jack therein; Fig. 3, a plan section of the base standard on line 3-3, Fig. 2,. the jack being removed therefrom; Fig. +1, a fragmentary section showing the pedestal standards telescoped together and showing the jack in side elevation therein; Fig. 5, a top view of the lifting arm; Fig. 6, a front elevation of the same; Fig. 7 a section of the same on line 7-7, Fig. 5; Fig. 8, a section of the lifting bracket showing the arm braces as on line 8-8, Fig. 6; Fig. 9, a vertical sectionshowing the pedestal standards extended with the jack removed therefrom; Fig. 10, a fragmentary view showing the ad justing screw chain; Fig. 11, a fragmentary view of the adjustable pulley block; Fig. 12, a plan view of the crank shaft and operating lever, showing the bearings in section; Fig. 13, a side elevation of the jack; Fig. 14, a top view of the jack with the cover removed; Fig. 15, a top view of the jack showing the cover thereon; Fig. 16, a vertical section of the release valve; Fig. 17, a fragmentary connection for the gearing view of the release-valve actuating rod showing the ledge and guide post thereon; Fig. 18, a plan view ofthe chair pedestal with the seat frame removed therefrom and showing a top view of the jack therein; Fig. 19, a vertical section of the jack on line 1919, Fig. 15; Fig. 20, a vertical section of thejack on line 20-20, Fig. 15; Fig. 21, a detached perspective view of the locking dog; and Fig. 22,- a'detached perspective view of the locking crank.

Similar numerals refer to similar parts throughout the drawings. The chair pedestal consists of the base plate 1, the base standard 2, the middle standard 3 and the top standard 4; on which top standard is formed or secured the seat frame 5.0f the chair, which carries the leg rest 6, the foot rest 7 the childs seat 8, the back rest 9 and the head rest 10, and the other parts usually pertaining to a dental or surgical chair. The several standards are made open at both ends, with slightly flattened cylindric walls, and are arranged to telescope one within the other, and are provided with the usual tongue 2 and 3 and groove 3 and 1 slide guides on each side.

The external rim flange 11 on the lower end of the base standard rests and rotates on' the inturned inverted L-shaped flange 12 on the base plate, which latter flange forms the annular groove 13 in the base plate. Two L-shaped lugs '14 depend from the base standard in the rear portion thereof, the lugs being preferably spaced apart on each side of themedianline, which lugs engage the inverted L-shaped flange 12 of the base plate;-,and the L-shaped dog 15 is provided in the aperture 11 formed in the forward portion of the flange 11 of the base standard, which dog is carried on the eccentric part 16 of the crank shaft 16 by rotation of which it is moved upward and downward to clamp its L tongue against the lower side of the base plate flange 12.

The clamping action of the dog 15 is controlled by adjustment of th set screw 17 in the dog operating against t e upper side of the crank, and the dogis adapted to swing upon the crank by an adjustment of the set screw 18 in the base standard and abutting the upper end of the dog, to cause the pendent shank thereof to press against the rim of thefiange 12 for holding the base pedestal in proper rotatable position on the base plate.

These parts are preferably shielded by the detachable'cap 19 having the apertured lug 19 therein which telescopes on the shank of the adjusting screw 17, which adjusting screw 17 is preferably clamped against turning by the set screw 19 'in the cap; which cap moves up and down with'the movement of the dog.

The jack 20 has its lower end seated in.

the forward and rear brackets'2 and 2 depending inside the lower end of the base standard, and is held in vertical positionby the apertured lug 20 on the forward left side of the jack, which lug telescopes on the upright post '24 extending upward from the bearing block 25in the lower left portion of the base standard.

The lifting bracket 26 is secured at its lower end to the inner side of the lower end of the middle standard 3, whence its shank extends upward inside the top standard,

andhasthe overhanging lifting-arm 27 detachably secured on its upper end, as by the cap screw 28, which lifting-arm overhangs and is abutted bythe upper end of the piston rod 29 of the jack, to which the liftingarm is preferably connected as by the bolt 30. The lifting-arm 27 is furthermore provided with the depending tongues 27 which abut the rear side portions of the bracket and brace the arm in its lifting action.

In each side of the middle standard is an endless chain 31 operating over a pulley wheel 32 and under an adjustable pulley block 33 mounted respectively in the upper and lower ends of the middle standard;

which chain is secured to the seat standard by the bolt 34and to the base standard by the adjustable bolt 35 on the upper end of the upright post 36 which rises from the bearing block 25 in the lower end of the base standard. It is obvious that, by this gearing, when the middle standard is raised by the piston rod 29 of the jack 20,'the top standard with the seat frame thereon will be carried upward at twice the speed of the middle standard, thus providing a quick and rapid elevation of the chair; and, at the same time, the endless chain serves to retain the standards in their relative positions when lowered, as, for instance, in event the top standard should stick from new paint or a gummy lubricant in the slides, the endless chain will force it downward. By these means, the top standard is positively lowered in the middle standard when the middle standard is lowered in the base standard.

The jack 20 is composed of the oil reservoir 21, the pump cylinder 22 in the lower end thereof, and the piston cylinder 23 edjacent to one side thereof; the lower ends of the reservoir and the two cylinders being preferably secured in the base block 36 of the jack in which is provided the transverse duct 37 communicating between the lower ends of the pump cylinder and the piston cylinder. The upper ends of the reservoir and the piston cylinder are preferably closed by the cover 38 under which is'provided the transverse channel 39 communicating between the upper ends of the piston cylinder, and the reservoir.

The spring-sustained check valve 40 is provided in the lower end of the pump cylinder and is arranged to permit a flow of oil into the piston cylinder through the communicating duct 37 and to prevent a return of the same; and the plunger head 41 and adjacent portion of the plunger rod 42 are provided with the axial duct 13 with the radial ports 44 in the wall of the rod above the plunger head, which duct and ports aflord communication between the portions of the pump cylinder above and below the plunger head; and the spring-sustained valve. 45 is provided for closing the duct against an upward flow of oil while per- Knitting a downward flow thereof through the duct.

The plunger rcd extends upward through the aperture 46 1n the cover 38 of the jack,

and on' the round upper end 47 thereof is mounted the inverted cup 48 which is adjustably secured as by screwing into the cross bar 49, the ends of which are engaged by the hooks 50 on the upper ends of the connecting bars 50, one being located on "the wall of the base standard and the bearing block 25 therein, as shown in Fig. 12.

The plunger is normally raised and held upward by action of the spring 57 around the plunger rod 42 between the cap 58 of the pump cylinder and the collar .59 on the plunger rod; and the ports 22 are provided in the wall of the upper-end of thepump cylinder. The piston head 60 is provided on the lower end of the piston rod 29, and the Oll reservoir, the pump cylinder and the piston cylinder being filled with oil it is evldent that an operation of the pump by the operators foot on the pedal 54 of the operating lever, will serve to extend the pedestal parts and raise the chair seat in theusual manner, and that such oil as may be 1n the piston cylinder abpve the piston head will overflow into the oil reservoir through the communicating I channel '39 at the upper end of the jack.

The release valve 61 is located in the tubular case 62 secured by the bracket 63 in the upper end of the oil reservoir, the radial port 64 being provided in the wall of the case, which, with the tube 64 and lateral ledge, even though the operators the port 64*, forms a release duct communi eating with the transverse duct 37 in the base block of the jack. The annular shoulder 65 in the valve case 62 forms the seat for the release valve 61; and, extending downward from the valve seat, is provided the discharge port 66 in which is located the inverted conical pin 67 and the upper end of the integral cylindrical pin 68, which cylindrical pin rests on the lateral ledge 69 secured on the upper end of the upright actuating rod 70 operating in the guides 71 and 71 and normally depressed by the spring 72,'the lower end of which rod is abutted by the crank arm 73 on the inner end of the shaft 74 of the release lever 75 provided with the pedal 75*, which shaft is journaled or fulcrumed in the flangell on the lower end of the base standard.

One or more discharge ducts as 66 lead from the discharge port 66, through the wall of the valve case 63, into the upper end of the oil reservoir, and it is evident that, by a depression of the pedal 75 of the release lever, the release valve will be opened and oil will bepermitted to flow from the lower end of the'piston cylinder 23 through the transverse duct 37 and the release duct into the release valve case 62, and thence through the discharge port 66 and duct 66 into the oil reservoir the rate of discharge being dependent upon the elevation of the inverted conical pin 67 which controls the size of the free opening in the upper end of the discharge port, the extreme elevation of which in turn is regulated by the adjustable screw 76 in the cover 38 which abuts and stops the upward movement of the actuating rod 70.

The guide post 77 rises from the lateral ledge 69 and extends upward through the guide aperture 78 in the cover 38 of the jack; which guide post serves to hold one edge 79 of the lateral ledge over the piston cylinder in the path of the piston head 60, so that an extreme upward movement of the piston rod causes the piston head to impinge and elevate the lateral ledge 69, thereby automatically opening the release valve 61 and preventing an excessive extension of the chair standard. On the other hand, the set screw 80 is provided in the flange arm 27 on the upper end of the piston bracket 26, which set screw is arranged to impinge the upper end of the guide rod 77 just before the extended standards are completely lowered, thus positively depressing the foot may be upon the release pedal, and gradually permitting the release valve to close, thus automatically cushioning the completion of the lowering of the chair.

The seat frame 5 is provided with the opening 81 above and substantially corre- 65 sponding with the open upper end of the top standard 4,

through which opening the jack as a whole may be readily enteredinto and removed from the pedestal of the chair, preferably when the same is lowered, as shown in Figs. 1 and i; it being understood that the lifting-arm 27 is detached from the upper end of the lifting bracket 26, and the hooks 50 of the connecting bars 50 are disengaged from the cross bar 19, for a removal of the jack, and that these parts are re-connected and 'reengaged when the jack is reentered into the pedestal of the chair. And it is evident that the hooks on the upper end of the connecting bars 50 are readily engaged and disengaged from the cross bar 4:9 by a downward adjustment of the cross bar 19 by the inverted screw cup 48.

It is also evident that, by a' removal of the cover of the jack, which may be readily done without removing the jack from the chair pedestal, all the interior parts of the jack can be reached for removal or inspection, it being understood that, to permit a withdrawal of the piston head, the lateral rod 70 to remove the edge 79 of the ledge from the path of the piston head; and finally, it is evident that oil can be supplied into the reservoir without removing the jack from the chair or the cover from the jack, by merely removing the screw plug 82 from the cover of the jack.

Furthermore, the peculiar constructionand arrangement of the chair and jack parts, permits the pedestal standards to be made without any openings in their walls, thus completely incasing the jack therein when the pedestal is extended as well as when the standards are telescoped together, and greatly improving the appearance as well as the cleanliness of the chair. And finally, the peculiar construction of the-crank shaft, the crank arms and the operating arms, permits the same to be made integral and the crank shaft with the arm thereon to be entered through the journal bearing in the wall of the base standard.

I claim:

1. In a chair, an extensible pedestal including a plurality of telescoping standards having open upper ends, a seat frame on the top standard having an opening therein cor responding to the open end of the standard,

and a jack removably seated in the base standard adapted to be entered and removed through the seat frame opening.

2. In a chair, an extensible pedestal including a plurality of telescoping standards having open upper ends, a seat frame on the top standard having an opening therein corresponding to the open end of the standard, a jack adapted to be entered and removed through said opening, a seat in the base ledge 69 is merely rotated with the release standard for the jack, an upright post in the base standard, and a lateral lug on the jack adapted to engage the post when seated in the base standard.

3. In a chair, an extensible pedestal including three telescoping standards having open upper ends, a seat frame on the top standard having an opening therein corresponding to the open end of the standard, a jack removably seated in the base standard having an upright piston rod therein, a lifting bracket connected to the lower end of the middle standard and extending upward inside the top standard, and a detachable lifting arm on the bracket abutting the upper end of the piston rod.

4. In a chair, an extensible pedestal including a plurality of telescoping standards, a jack seated in the base standard having a piston therein with an upright rod, a lifting arm secured to' one of the standards abutting the upper end of the piston rod, a release valve in the jack, and an actuating rod having a lateral ledge in the path of the piston and extending under the release valve to operate the same.

In a chair, an extensible pedestal including a plurality of telescoping standards, a jack seated in the base standard having a piston cylinder with an upright piston rod, a lifting arm secured to one of the standards abutting the upper end of the piston rod, a release valve in the jack, an actuating rod having a lateral ledge thereon extending under the release valveand having one edge extending into the piston cylinder above the piston head, and a pin on the ledge for opening the valve.

- 6. In a chair, an extensible pedestal including a plurality of telescoping standards, a jack seated in the base standard having an upright piston rod, a lifting arm secured 'to one of the standards abutting the upper end of the piston rod, a release valve in the'jack, an actuating rod having a lateral ledge extending under the release valve, a pin on the ledge for opening the valve, means in the base standard for raising the actuating rod stop in the jack for limiting the upward movement of the actuating rod. 8. In achair, a base plate having an 1nturned L-shaped flange with an annular groove thereunder, a pedestal rotatably seated on the base flange with L tongues spaced apart on one side engaging the base flange, and a crank shaft in the other side of the pedestal with an l. dog thereon engaging the base flange, there being an adjusting screw in the dog impinging the upper side of the crank and an adjusting screw in the pedestal for rocking the dog on the crank.

9. In a chair, a base pedestal having a journal bearing in one wall and a journal socket in the opposite wall, a crankshaft with an integral operating lever having a journal adjacent to the lever for the bearing and a journal pin on the end for the socket, a lateral bar forming a crank arm on the shaft adjacent to, its end and a lateral bend in the rock shat't forming a crank arm adjacent to the journal bearing.

10. In a chair, an extensible pedestal including a plurality ot' telescoping standards, a removable jack seated in the base standard having an upright valve-actuating rod thereon, and a crank arm fulcruined in the base standard abutting the lower end of the rod.

FRANK It. CASE.

lVitnesses lnnar A. ll. 'luuRELL, Funo J. Znrrmzu. 

